U.S. patent application number 10/882642 was filed with the patent office on 2006-01-05 for methods of monitoring the concentration of an analyte.
Invention is credited to Manfred Ebner, Ulrich Kraft, Joseph McCluskey, Matthias Stiene.
Application Number | 20060001538 10/882642 |
Document ID | / |
Family ID | 34941685 |
Filed Date | 2006-01-05 |
United States Patent
Application |
20060001538 |
Kind Code |
A1 |
Kraft; Ulrich ; et
al. |
January 5, 2006 |
Methods of monitoring the concentration of an analyte
Abstract
Methods are disclosed for remotely monitoring an analyte
concentration of an individual by one or more other
individuals.
Inventors: |
Kraft; Ulrich; (Hofheim,
DE) ; Ebner; Manfred; (Oberusel, DE) ; Stiene;
Matthias; (Gilching, DE) ; McCluskey; Joseph;
(Sharon, MA) |
Correspondence
Address: |
BOZICEVIC, FIELD & FRANCIS LLP
1900 UNIVERSITY AVENUE
SUITE 200
EAST PALO ALTO
CA
94303
US
|
Family ID: |
34941685 |
Appl. No.: |
10/882642 |
Filed: |
June 30, 2004 |
Current U.S.
Class: |
340/539.12 ;
128/903; 600/300 |
Current CPC
Class: |
A61B 5/0031 20130101;
A61B 5/14532 20130101 |
Class at
Publication: |
340/539.12 ;
128/903; 600/300 |
International
Class: |
A61B 5/00 20060101
A61B005/00; G08B 1/08 20060101 G08B001/08 |
Claims
1. A method of monitoring an analyte concentration of a first
person by at least one secondary person, the method comprising:
measuring the analyte concentration of the first person;
transmitting a first wireless signal representative of a real-time
status of the analyte concentration, the first signal having a
first transmission range; and transmitting a second wireless signal
representative of the real-time status of the analyte concentration
to the location of the at least one secondary person, the second
wireless signal having a second transmission range; wherein the
second transmission range is greater than the first transmission
range.
2. The method of claim 1, wherein a signal frequency of the first
wireless signal is in the range from about 200 MHz to about 950 MHz
and a signal frequency of the second wireless signal is about 2.4
GHz.
3. The method of claim 1, wherein the first wireless signal is
transmitted about 3 meters or less and the second wireless signal
is transmitted up to about 30 meters or more.
4. The method of claim 1, further comprising activating an alarm at
the location of the at least one secondary person in response to
the real-time status of the analyte concentration.
5. The method of claim 4, further comprising activating an alarm at
the location of the first person in response to the real-time
status of the analyte concentration.
6. The method of claim 1, wherein in the analyte measuring is
performed continuously.
7. The method of claim 6, wherein the analyte measuring is also
performed episodically.
8. A method of relaying a real-time analyte concentration of a
first person by at least one secondary person, the method
comprising: measuring the analyte concentration of the first person
with a sensor; transmitting a first wireless signal representative
of a real-time status of the analyte concentration from the sensor
to a handheld device located a first distance from the sensor, the
first signal having a first transmission range; transmitting a
second wireless signal representative of the real-time status of
the analyte concentration from the handheld device to a relay
located a second distance from the sensor, the second wireless
signal having a second transmission range; and transmitting a third
wireless signal representative of the real-time status of the
analyte concentration from the relay to at least one signal
receiver located a third distance from the sensor, wherein the
third wireless signal has a transmission range than the
transmission range of the first wireless signal.
9. The method of claim 8, further comprising activating an alarm at
the location of the at least one secondary person in response to
the real-time status of the analyte concentration.
10. The method of claim 8, wherein the third distance is
substantially greater than the first distance.
11. The method of claim 8, wherein the first distance and the
second distance are substantially the same.
12. The method of claim 8, wherein the third wireless signal has a
signal frequency greater than a signal frequency of the second
wireless signal. TABLE-US-00001 US Patent/Application/
Inventor/Applicant Publication No. Publication/Issue Date Mann WO
0019887 Pfeiler US 5558640 Bernson US 4676248 Russo US 6135949
Khair US 6441747 Levitas US 6053887 Mann US 6551276 Causey US
20020002326
13. The method of claim 8, wherein the third wireless signal has a
transmission protocol different from a transmission protocol of the
second wireless signal.
Description
BACKGROUND
[0001] There is a need to measure and monitor analyte
concentrations in a continuous or in a frequent, periodic manner.
For example, certain diabetics benefit from a system that can
measure glucose concentration levels continuously and automatically
without the need for human intervention. A variety of such systems
exist, including those having sensors which are permanently or
temporarily implantable or which. establish continuous access to
the patient's blood or interstitial fluid. Such systems provide
diabetics with real-time glucose concentration levels.
[0002] It is contemplated that these systems include an alarm
mechanism that is automatically activated to notify the user when
his or her glucose level is outside of a physiologically normal
zone. This would be especially useful for the nocturnal monitoring
of diabetics. In such a scenario, when the patient enters a hypo or
hyperglycemic state, the continuous glucose sensor activates an
acoustical alarm (located either on the sensor itself or on a
separate but closely positioned unit which is wired to or in
wireless contact with the sensor) to wake up the diabetic person so
that the appropriate therapy can be invoked. In certain cases,
however, the alarm may not be sufficient to wake up the diabetic,
particularly in situations where the diabetic is unable to be
easily woken or has gone into a comatose state due to the hypo or
hyperglycemic condition. Such an alarm is also not useful in
situations where the diabetic is a baby or a very young child or is
otherwise physically or mentally handicapped and unable to help
himself in response to the alarm. In these situations, a parent or
other caretaker must frequently and regularly check on the diabetic
to monitor the diabetic's glucose level.
[0003] While wireless technologies are available to enable remote
placement of an alarm, such as in the parent or caretaker's
bedroom, due to Federal Communications Commission (FCC)
regulations, these types of sensor systems are required to use a
very low transmission frequency which limits placement of the alarm
to no more than several meters from the sensor. Low frequency
devices and specifically their antennas are necessarily relatively
large. On the other hand, sensor-alarm systems capable of
transmitting high frequency (above about 100 MHz) are subject to
interference by the human body and, thus, have limited transmission
range capacity, especially indoors. Additionally, high frequency
wireless signals can consume large amounts of power requiring a
battery size that limits portability of the alarm unit.
[0004] Accordingly, there is a continued need for the development
of new devices and techniques for facilitating the remote
monitoring of real-time analyte levels and other physiological
characteristics that address the shortcomings of current
technologies.
SUMMARY
[0005] The present invention is directed to methods of monitoring
analytes that satisfy the need to remotely monitor a patient and to
remotely transmit patient data and/or to activate an alarm that
obviates the drawbacks and shortcomings of prior systems. Further,
the subject methods utilize systems which consume minimal power,
provide relatively long-range signal transmissions and are less
inclined to have interference with the human body than conventional
analyte monitoring systems.
[0006] The analyte monitoring systems include a sensor for
monitoring an analyte concentration of a user, a signal relay, and
a signal receiver. In addition to monitoring analyte
concentrations, the sensor is configured to transmit a first
wireless signal to the signal relay which signal is representative
of a real-time analyte concentration level, e.g., a value
representative of a current glucose level, or a physiological
state, e.g., hypo- or hyperglycemia. The signal relay is configured
to receive the first wireless signal and to, in turn, transmit a
second wireless signal to the signal receiver which is
representative of such concentration level or state, wherein the
second wireless signal has a different frequency and/or
transmission protocol (i.e., including but not limited to signal
transmission and reception times and data packaging (e.g.,
addressing, encoding, etc.)) than that of the first wireless
signal. The signal receiver is configured to receive the second
wireless signal and to provide notification to a user of the actual
real-time analyte level, sensor state (function status, failure
occurrence, error code, etc.) or a state representative thereof.
Such notification may be an audible, tactile and/or visual alarm
and may further include a display of the actual analyte
concentration value. Accordingly, the analyte monitoring systems of
the present invention can transmit an alarm by using a first
frequency to communicate with the sensor to the relay over a
relatively short distance, and subsequently using a second
frequency to communicate with the relay to the receiving device
over a relatively longer distance. The two signals may have the
same or different frequencies. If the same frequency is used, the
signals typically have different transmission protocols which do
not interfere with each other.
[0007] A method of the present invention is directed to monitoring
an analyte concentration of a first person by at least one
secondary person. The method includes measuring the analyte
concentration of the first person and transmitting a wireless
signal representative of a real-time status of the analyte
concentration value. A second wireless signal representative of the
real-time status of the analyte concentration the concentration
value having is then transmitted to the location of the at least
one secondary person. The transmission range of the second signal
is greater than the transmission range of the first signal.
[0008] Another method of the present invention is directed to
relaying a real-time analyte concentration value of a first person
by at least one secondary person. This method includes measuring
the analyte concentration of the first person with a sensor and
transmitting a first wireless signal representative of the
real-time status of the analyte concentration from the sensor to a
handheld device located a first distance from the sensor. A second
wireless signal representative of the concentration value is then
transmitted from the handheld device to a relay located a second
distance from the sensor. A third wireless signal is then
transmitted from the relay to at least one signal receiver located
a third distance from the sensor, wherein the third wireless signal
has a transmission range greater than the transmission range of the
first wireless signal.
[0009] These and other objects, advantages, and features of the
invention will become apparent to those persons skilled in the art
upon reading the details of the invention as more fully described
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The invention is best understood from the following detailed
description when read in conjunction with the accompanying
drawings:
[0011] FIG. 1 is a schematic illustration of a first embodiment of
an analyte monitoring system of the present invention.
[0012] FIG. 2 is a schematic illustration of a second embodiment of
an analyte monitoring system of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0013] Before the subject systems and method are described, it is
to be understood that this invention is not limited to particular
embodiments described or illustrated, as such may, of course, vary.
It is also to be understood that the terminology used herein is for
the purpose of describing particular embodiments only, and is not
intended to be limiting, since the scope of the present invention
will be limited only by the appended claims.
[0014] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
unless the context clearly dictates otherwise, between the upper
and lower limits of that range is also specifically disclosed. Each
smaller range between any stated value or intervening value in a
stated range and any other stated or intervening value in that
stated range is encompassed within the invention. The upper and
lower limits of these smaller ranges may independently be included
or excluded in the range, and each range where either, neither or
both limits are included in the smaller ranges is also encompassed
within the invention, subject to any specifically excluded limit in
the stated range. Where the stated range includes one or both of
the limits, ranges excluding either or both of those included
limits are also included in the invention.
[0015] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs.
[0016] It must be noted that as used herein and in the appended
claims, the singular forms "a", "an", and "the" include plural
referents unless the context clearly dictates otherwise. Thus, for
example, reference to "a signal" includes a plurality of such
signals and so forth.
[0017] All publications mentioned herein are incorporated herein by
reference to disclose and describe the methods and/or materials in
connection with which the publications are cited. The publications
discussed herein are provided solely for their disclosure prior to
the filing date of the present application. Nothing herein is to be
construed as an admission that the present invention is not
entitled to antedate such publication by virtue of prior invention.
Further, the dates of publication provided might be different from
the actual publication dates which may need to be independently
confirmed.
[0018] Exemplary embodiments and variations of the present
invention will now be described in detail. In further describing
the present invention, the subject systems and device components
will be described first. Next, various methods of using the subject
devices and systems as well as methods for the transmission of
real-time physiological information will then be described.
Finally, a brief description is provided of the subject kits, which
kits include the subject devices and systems for use in practicing
the subject methods.
[0019] In the following description, the present invention will be
described in the context of glucose concentration measurement;
however, such is not intended to be limiting and those skilled in
the art will appreciate that the subject devices, systems and
methods are useful in the measurement and monitoring of other
physical, neurological and chemical characteristics, e.g., blood
pressure, heart rate, respiratory rate, neurological activity,
therapeutic drug levels, fetal activity, sleep states, etc.
[0020] FIG. 1 is a schematic representation of an embodiment of an
analyte monitoring system of the present invention. Analyte
monitoring system includes an analyte sensor 100, a signal relay 4,
and a signal-receiving device 6.
[0021] Sensor 100 may be any suitable type of sensor, including but
not limited to one that is permanently or temporarily implantable
through or within subcutaneous, dermal, sub-dermal,
intra-peritoneal or peritoneal tissue or is otherwise worn or
attached to the body allowing continuous or intermittent
measurement and access to the user's blood, interstitial fluid or
the like. The sensors may be electrochemical, chemical or optical
sensors or the like. Examples of such sensors which may be used
with the present invention are disclosed in U.S. Pat. Nos.
6,040,194; 6,232,130; 6,233,471; 6,272,364; 6,329,161; 6,514,718;
6,558,321 and 6,702,857, and in International Publication WO
02/49507, which are fully incorporated by reference herein.
Examples of commercially available sensors usable with the present
invention include but are not limited to GlucoWatch G2.RTM.
Biographer from Cygnus, Inc., Redwood City, Calif.; CGMSO System
Gold.TM. from Medtronic Minimed, Inc., Northridge, Calif.
[0022] Sensor 100 may include an integrated signal transmitter or
one that is directly coupled to the sensing portion of the sensor.
The transmitter is preferably configured to transmit signals within
the radio frequency (RF) spectrum. The sensor further includes a
processor which may be programmed to enable the sensor to make
continuous or intermittent but frequent measurements of the target
analyte(s) and to transmit signals representative of those
measurements continuously or intermittently. With non-implantable
or partially implantable sensors, the sensor itself may also be
configured to provide an alarm to the user to indicate a less than
acceptable analyte measurement. With implantable sensors, the
sensor may be configured to transmit a signal to activate an
external alarm adjacent the user. Additionally, the sensor's
processor may enable the detection of sensor malfunction, e.g., due
to low battery power, temperature extremes, disconnection of the
sensor from the user, etc., and the transmission of alarm signals
representative of those malfunctions.
[0023] Signal relay 4 includes a signal-receiving portion
configured to receive transmitted signals from sensor 100 and a
transmitting portion configured to transmit signals to signal
receiver 6. Again, the receiving and transmitting portions are
preferably configured to operate within the RF band. Relay 4 is
further configured to convert a received signal having one
frequency and/or transmission protocol to a signal having another
frequency and/or transmission protocol, and to transmit the
converted signal having a transmission range greater than that of
the received signal. Suitable relays which may be used with the
present invention include those by Millenial Net, Inc. and ZigBee,
Inc.
[0024] Depending on the user's setup, relay 4 may be used as a
stationary and/or portable device. For example, relay 4 may be
integrated into a substantially stationary base unit or station, as
illustrated in FIG. 1, which may be powered by a designated power
supply or by a wire or cable connection to a conventional AC
outlet. With the relatively low energy signals transmitted by
sensor 100, better results are achieved when the relay 4 is placed
within about 3 meters from sensor 100. In one embodiment of this
invention, relay 4 may be positioned in the room where a diabetic
user resides. Alternatively, as illustrated in FIG. 2, relay 4 may
be configured to interface with a handheld, battery-powered unit 2.
Handheld device 2 may be configured to mate with relay 4 in a
modular fashion using an electrical socket union such as a USB port
wherein device 2 communicates information (signals) to relay 4 and
relay 4 is powered by device 2. Alternately, relay 4 may be
electrically integrated within handheld unit 2.
[0025] Handheld device 2 may also have the electronic functionality
to measure an analyte concentration such as glucose in an episodic
manner using a disposable glucose test strip. An example of an
episodic glucose meter that can be incorporated into handheld
device 2 is the commercially available LifeScan OneTouch.RTM.
UltraSmart.TM. Monitoring System. Under certain situations it may
be desirable for a system to measure glucose episodically in
addition to the continuous method. For example, episodic glucose
measurements may be needed to help calibrate sensor 100, perform a
quality control check, make an emergency glucose measurement test
while sensor 100 is equilibrating, or to confirm an extremely high
or low measurement made by sensor 100 before taking drastic
therapeutic actions. In another embodiment of the invention,
handheld device 2 can be used as a remote control device sending
and receiving data from sensor 100, an insulin pump (not shown),
and other medical devices.
[0026] With any of the relay configurations described above, the
base unit or handheld unit or both may include user interface
controls for controlling sensor function as well as a display for
displaying analyte values and other system parameters. The unit
also typically includes a primary alarm, such as an audible,
tactical (vibration) and/or visual (flashing LED) alarm signal, to
notify the user of a critical or potentially critical state.
Because relay 4 has an AC power source, it can generate a stronger
alarm, e.g., a louder noise or a brighter light, than one that is
generated solely from sensor 100 to help alert the diabetic user.
Where sensor 100 is used in conjunction with an insulin pump as
part of a closed-loop or feedback control system to control
delivery of the appropriate dosage of insulin to maintain a
euglycemic state, such an alarm may not be necessary. However,
where such a closed-loop system is not employed, this primary alarm
alone may not be sufficient to wake up a user when the user's
glucose levels have reached a critical state.
[0027] Signal receiver 6 is configured to receive the higher energy
signals from relay 4 and, as such, may be placed further away from
relay 4 than the distance relay 4 is able to be placed from sensor
100, i.e., greater than about 3 meters. Receiving device 6 may be
configured to be stationary whereby it is placed in a location or
room (e.g., a bedroom, nurses' station) where a secondary person or
user (e.g., parent, caregiver, nurse, etc.) is located. The
stationary receiver may be battery powered or powered via an AC
outlet source. Alternately, receiving device 6 may be a portable,
battery-powered device which is configured to be worn or carried by
the secondary person such as, for example, with a belt clip or on
an armband.
[0028] With either of the signal receiver configurations, the
receiver provides a secondary system alarm, such as an audible, a
tactical (vibration) and/or a visual (e.g., one or more flashing
light emitting diodes (LED)) alarm mechanism which is activated
when the analyte concentration is outside of a physiological normal
zone. In this way, the secondary user is immediately alerted to a
critical or potentially critical state being experienced by the
primary (e.g., diabetic) user. In one embodiment, an audible alarm
may be configured to emit various volume (decibel) levels depending
on the urgency or type of situation at hand. For example, a more
urgent situation, e.g., the primary user's glucose levels have
entered a physiological critical zone, would be provide a very loud
alarm while. Alternatively, the alarm sound may be a recorded voice
which literally announces the primary user's real-time status,
e.g., "urgent", "caution", etc. Also, the type of sound may vary
depending on the situation necessitating an alarm. For example, a
beeping sound may be emitted for signaling the primary user's
physiological status while a buzzing sound may be emitted for
signaling a system problem, e.g., low battery, loss of signal
reception, etc. Visual alarms may be configured to emit a plurality
of colors, for example, where green indicates that the primary user
is in a euglycemic state, yellow indicates that the primary user is
in or entering a potentially hypo or hyperglycemic zone, and red
indicates that the primary user's glucose level has entered unsafe
hypo or hyperglycemic zone, where a blue light indicates a system
failure or problem.
[0029] Receiving device 6 may further include a display, such as a
liquid crystal display (LCD), which displays quantitative and/or
qualitative real-time or stored (e.g., primary user information
data about the primary user, e.g., a real-time measurement or
several recently taken measurements of the primary user's glucose
concentration. The display may also provide information regarding
system parameters, e.g., remaining battery power, signal reception
level, etc. As with the base unit or handheld unit associated with
relay 4, signal receiver 6 may provide user interface controls such
as functional menus, volume adjustment, etc.
[0030] So configured, the systems of the present invention enable
wireless signals, i.e., alarm signals as well as information
representative of analyte measurement and system operation
parameters, to be transmitted to signal receiving device 6 from
sensor 100 via signal relay 4. In other words, relay 4 is used as a
conduit to transmit information to a person remotely located from a
monitored individual. The system may include one or more additional
signal receivers placed in different locations so as to transmit
information to more than one person. In the context of the
application discussed herein, the subject systems provide a
convenient way to wirelessly alert one or more secondary persons
about the glycemic status of a monitored diabetic.
[0031] Typically, the distance between the monitored individual and
the secondary person is about 30 to 100 meters but may be more or
less depending on the size of the building (e.g., home, hospital
ward, etc) or area in which they users are located. Such a
transmission range necessitates a signal transmission frequency
that is greater than the allowable frequency range of sensor 100.
Notwithstanding the federal regulations limiting medical sensor
frequency ranges, practicality dictates that the size of sensor 100
be relatively small, e.g., no more than about a few cubic
centimeters cubed, particularly if implanted, and thus having
limited space capacity in which to house a battery or efficient
antenna. Thus, only very small batteries having a low energy output
are suitable for use with sensor 100. Due to the limited power
supply, the range of signal transmission by sensor 100 is limited
and the energy of the signals transmitted by sensor 100 is
relatively low, e.g., no more than several hundred microwatts.
[0032] According to the present invention, signal relay 4 is
employed to compensate for the limited range of transmission of
sensor 100. As signal relay 4 is not implanted within the body, and
in certain embodiments is not worn by the primary user, it does not
have the size, space, transmission range and power constraints of
sensor 100. As such, relay 4 is usable with a larger power supply
source and is able to transmit signals at a higher energy over a
longer distance. Although the higher energy is more susceptible to
absorption by the body, the relay is remote enough to minimize such
absorption.
[0033] Sensor 100 wirelessly communicates with relay 4 by means of
a first transmission signal having a first frequency 8a and
employing a first transmission protocol, and relay 4 wirelessly
communicates with signal receiver 6 by means of a second
transmission signal having a second frequency 8b and employing a
second transmission protocol. If the same frequency is used for
both, then the two transmission protocols are different, and
visa-versa. Alternatively, both frequencies and both transmission
protocols may be different. With any embodiment, first frequency 8a
is sufficient to allow wireless communication from sensor 100 to
relay 4 over a distance of no more than about 3 meters, and second
frequency 8b is sufficient to allow wireless communication to occur
between relay 4 and receiving device 6 over a distance greater than
about 3 meters, and most typically up to about 30 to about 100
meters. Of course, the total transmission distance may be expanded
as necessary by using one or more successively spaced relays.
[0034] In the embodiment of FIG. 2, handheld unit 2 may wirelessly
communicate with relay 4 using a third transmission signal having a
third frequency 8c employing a third transmission protocol
sufficient to allow wireless communication to occur between unit 2
and relay 4 over a distance similar to the distance between sensor
100 and relay 4, but such distance may be greater or smaller. The
third signal may have the same or a different frequency and/or
utilize the same or a different transmission protocol as the first
signal.
[0035] For practical reasons, signals within the radio frequency
spectrum are preferable for applications of the present invention.
Typically, the transmission signals used in the present invention
have frequencies in the range from about 200 MHz to greater than
2.4 GHz. In one variation, the first and/or third frequencies 8a,
8c are typically in the range from about 200 MHz to about 950 MHz,
and second frequency 8b is about 2.4 GHz (which enables the use of
802.11 wireless standards), but may be higher or lower as the
application dictates. In one embodiment, either or both first and
third frequencies are about 903 MHz (which frequency is available
as part of the unlicensed spectrum of radio frequencies).
[0036] The wireless communication within the described systems may
be entirely unidirectional, i.e., from the sensor to the relay to
the receiver, or entirely bidirectional, i.e., the receiver may be
able to transmit to the relay which is able to transmit to the
sensor, or the systems may be partially unidirectional and
partially bidirectional, e.g., communication between the sensor and
relay or handheld unit may be bidirectional while communication
between the relay and the signal receiver may be unidirectional.
The frequencies of the signals transmitted in the opposite
direction to what has been primarily described herein (i.e.,
transmissions from the receiver to the relay and from the relay to
the sensor) may be the same or different from frequencies 8a, 8b
and 8c, respectively.
[0037] The present invention further includes methods for
monitoring an analyte concentration of a first person by at least
one secondary person. In one variation, the method involves
measuring the analyte concentration of the first person, such as
with sensor 100 described above, and then transmitting a
lower-energy wireless signal representative of a real-time status
of the analyte concentration and/or an alarm reflective of such
status to a relay station, such as with relay 4 described above
(and/or to a handheld or base unit 2), where it is converted to a
higher-energy wireless signal. The higher-energy signal is then
transmitted to the secondary person at the location, and is
received at the second location by of signal receiver, such as
signal receiver 6 described above. An alarm on the signal receiver
may be activated to alert the secondary person in response to an
analyte concentration level of the first person which is outside an
acceptable range. Additionally, the sensor and/or relay and/or
handheld unit may have respective alarms which are activated under
similar circumstances.
[0038] With the embodiment of FIG. 2, the first wireless signal may
be sent simultaneously to both the handheld unit 2 and the relay 4,
or may be sent to one or the other first which may then transmit a
second wireless signal to the other. Typically, the first signal is
sent to the handheld unit which in turn transmits it to the relay.
As mentioned above, the handheld unit may transmit signals having
the same or different energy as the sensor.
[0039] It is an advantage of this invention in that the first
frequency range requires relatively low power and is less inclined
to have interferences with the human body where sensor 100 is
likely to be situated. A further advantage of the low power
requirement is that it allows sensor 100 to have a smaller battery
and/or less frequent battery charging/replacement which is highly
desirable for both implanted and wearable continuous sensors.
However, as discussed above, a lower energy signal generally causes
the range of transmission to be limited. Relay 4 is thus used to
relay the transmission of signals (i.e., information and data) from
sensor 100 to receiving device 6.
[0040] It is a further advantage of the present invention in that
second frequency 8b allows a much larger transmittal range.
Although second frequency 8b requires relatively more power than
first frequency 8a, the use of a stationary relay 4 using an AC
power source or a large battery having higher energy output, thus,
mitigating the power issue. It should be noted that the use of a
higher-energy signal is more inclined to have physiological
interferences with the human body, but this is typically not an
issue as relay 4 is usually remote from a human body.
[0041] Also provided by the subject invention are kits for use in
practicing the subject methods. The kits of one embodiment of the
subject invention include at least one sensor, a relay and at least
one receiver, as described above. The kits may further include
software programs recorded on a CD-ROM or the like, which programs
may be downloaded to the sensor, a base or handheld unit or meter,
and/or a signal receiver by a user or a physician by means of an
external device, such as a computer. Finally, the kits may further
include instructions for using the subject devices. These
instructions may be present on one or more of the packaging, label
inserts or containers within the kits, or may be provided on a
CD-ROM or the like.
[0042] It is evident from the above description and discussion that
the above-described invention provides a simple and convenient way
to wirelessly alert one or more secondary persons about the
real-time glycemic status of a monitored diabetic. As such, the
subject invention represents a significant contribution to the
art.
[0043] Although the foregoing invention has been described in some
detail by way of illustration and example for purposes of clarity
of understanding, it is readily apparent to those of ordinary skill
in the art in light of the teachings of this invention that certain
changes and modifications may be made thereto without departing
from the spirit or scope of the appended claims.
* * * * *